The proposed research is directed at analyzing the mechanisms responsible for the development of ordered connectivity in the anuran visual system. Electrophysiological techniques will be used to determine the pattern of retino-tectal connections in normal adult animals and to compare these to the patterns in animals subject to various experimental interventions. Experimental paradigms will include regeneration, compression, and modification of sensory experience. In addition, normative studies will be made of the visual projections to anterior thalamus and thence to forebrain. The principal questions of interest are how exclusive are the synaptic potencies of individual neurons, and what is the involvement of sensory experience in nervous system development? An important distinction between this proposal and previous research is an emphasis on documenting the distribution of functional synapses in experimental animals.